// Copyright 2011 The Walk Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build windows

package walk

//单次执行的事件处理函数
type eventHandlerInfo struct {
	handler EventHandler
	once    bool
}

type EventHandler func()
//事件列表对象
type Event struct {
	handlers []eventHandlerInfo
}
//增加事件到列表
func (e *Event) Attach(handler EventHandler) int {
	handlerInfo := eventHandlerInfo{handler, false}

	for i, h := range e.handlers {
		if h.handler == nil {
			e.handlers[i] = handlerInfo
			return i
		}
	}

	e.handlers = append(e.handlers, handlerInfo)

	return len(e.handlers) - 1
}
//从列表中删除事件
func (e *Event) Detach(handle int) {
	e.handlers[handle].handler = nil
}

func (e *Event) Once(handler EventHandler) {
	i := e.Attach(handler)
	e.handlers[i].once = true
}
//事件发布对象
type EventPublisher struct {
	event Event
}
//返回事件列表
func (p *EventPublisher) Event() *Event {
	return &p.event
}
//遍历执行一遍窗体的所有事件
func (p *EventPublisher) Publish() {
	// This is a kludge to find the form that the event publisher is
	// affiliated with. It's only necessary because the event publisher
	// doesn't keep a pointer to the form on its own, and the call
	// to Publish isn't providing it either.
//	log.Println("-----------------------------------------------")
//	log.Printf("EventPublisher 事件广播:%s",debug.Stack())
	if form := App().ActiveForm(); form != nil {
		fb := form.AsFormBase()
		fb.inProgressEventCount++
		//在遍历执行窗体事件后,要更新一遍事件列表
		defer func() {
			fb.inProgressEventCount--
			if fb.inProgressEventCount == 0 && fb.layoutScheduled {
				fb.layoutScheduled = false
				fb.startLayout()
			}
		}()
	}
	//遍历窗体事件
	for i, h := range p.event.handlers {
		if h.handler != nil {
			//log.Println("EventPublisher函数回显------------")
			//pc := reflect.ValueOf(h.handler).Pointer()
			//f := runtime.FuncForPC(pc)
			//log.Println(f.Name())
			//log.Println(f.FileLine(pc))

			h.handler()	//执行窗体事件

			if h.once {
				p.event.Detach(i)
			}
		}
	}
}
